Transmitter plate potential equalizing circuit



Jul 7, 1931. URTEL 1,813,688

TRANSMITTER PLATE POTENTIAL EQUALIZING cmcum Filed Jan. 28. 1929 gave M 02 RUDOLF URTEL Patented July 7, 1931 STATES PATENT o rics RUDOLF URTEL, OF BERLIN, GERMANY, ASSIGNOR TO TELEFUNKEN GESELLSOI-IAFT FOR DRAHTLOSE T'ELEGRAPI-IIE M. B. H., OF BERLIN, GERMANY, A CORPORATION OF GERMANY TRANSMITTER PLATE POTENTIAL EQUALIZING CIRCUIT Application filed January 28, 1929, Serial No. 335,507, and in Germany March 26, 1928.

This invention relates to a tube transmitter arrangement and has particular reference to an equalizing circuit for a tube transmitter adapted to maintain the plate potential of the transmitter tubes at a constant value.

- to lead to frequency fluctuations. This objection is eliminated by the adoption of equalizing or compensating circuit arrangements. The latter consist in employing special tubes during the spacing periods, to ab- Sorb or take up all or part of the current from such stages as are rendered inoperative (mostly the main transmitter).

In the case of arrangements where the chief object is to maintain the plate potential of the preceding cascades at a constant value rather than to insure constancy of the plate potential source, a considerably smaller load equalizing tube is required, if, as is mostly true, the preceding stages are operated at lower plate potentials, and if for this purpose a series resistance is connected in the plate circuit of the lower stages. The load equalizing tubes are so connected that the current absorbed by them is made to flow through this series resistance. In this case the current to be taken up by this tube is a fraction of what is ordinarily involved.

One embodiment of the idea underlying the invention is illustrated by way of example in the accompanying drawing. The novel features which I believe to be characteristic of my invention are set forth in particularity in the appended claims, the invention itself, however, as to both its organization and method of operation will best be understood by reference to the following description taken in connection with the drawing in which I have indicated diagrammatically one circuit arrangement whereby my invention may be carried into effect. A main transmitter tube R is connected with the feed line +H H. This tube is coupled to the oscillation circuit S, and is subject to the control of the pilot transmitter St which is connected by the conventional regenerative coupling. The pilot transmitter receives the working potential by way of re sistance' W.

Now, according to this invention, an equalizer tube A is connected in parallel to the pilot tube, which is operated in dependence upon the oscillations in oscillation circuit S in the following manner. .Radio frequency current is absorbed from the oscillation circuit S' by way of transformer T, this current then being rectified in rectifier G so that a negative biasing potential is set up at the condenser. C whereby the tube A is stoppered. Now, this biasing potential varies in dependence upon the keying of tube R.

hen the key M is opened, the oscillations in circuit S cease and the negative potential biasing the load-equalizing tube A disappears. As a resultaheavier current is caused to flow through resistance W, and the potential fall across it grows. The proportions of tube A are so chosen, and the working conditions areso fixed, that the growth inpotential fall across resistance W just compensates the growth of potential in the supply line, which is caused by the opening of key M.

The embodiment illustrated is shown by way of preference only, hence the appended claims should be construed as broadly as permissible in view'of the prior art.

What I desire to claim is 1. A transmitter comprising, in combination, a plurality of thermionic tubes in cascade, one of said tubes being a pilot transmitter and another a main transmitter, a source of plate potential therefor, an operating key between said source and said main transmitter tube, an oscillation circuit between said key and main transmitter tube, said pilot tube being regeneratively coupled to said transmitter tube, an equalizing tube in parallel with said pilot tube, a rectifier circuit coupled to said oscillation circuit and connected to said equalizing tube and adapted to stopper the latter when said key is closed,

and a series resistance connected in the plate circuit of said parallel tubes.

2. In a transmitting circuit, a main transmitter tube, a pilot tube coupled to said first tube, a source of plate potential connected to both tubes, a series resistance connected in the plate circuit of said pilot tube, a load equalizing tube connected in parallel with said pilot tube, modulating means in the plate circuit of said first tube, means coupled to the plate circuit or" said first tube and connected to said equalizing tube adapted to render said equalizing tube inoperative when said first tube is operative, said series resistance and equalizing tube being so proportioned that the plate potential of said pilottubeis maintained constant regardless of current variations in the transmitter tube plate circuit.

3. A transmitter circuit comprising a pilot tube, a power tube coupled thereto, a source of plate potential connected to both tubes, an oscillation circuit in the plate circuit of said power tube, a resistance means in the plate circuit of said pilot tube, means in said power tube plate circuit to control the current flow therein, a load equalizing tube in parallel with said pilot tube, means coupled to said oscillation circuit and between the grid and filament of said equalizing tube to render said tube inoperative when the power tube plate circuit is closed.

l. The method of operating a space discharge oscillator and a space discharge repeater each having an input and a space current circuit, which consists in impressing waves from the oscillator upon the input of the repeater, rectifying a portion of the amplified waves of the repeater, and utilizing the direct current component or the rectified waves to maintain a constant average potential on the output circuit the oscillator.

5; In combination in a space discharge transmitter circuit, a space discharge oscillator and a space discharge repeater con nected in cascade, a load equalizing space discharge device connected in parallel to said oscillator, a source of anode potential for said oscillator and repeater, an impedance connected between said source and the anodes of said equalizing tube and oscillator, and means connected between the output circuit ofsaid repeater and the input circuit of said equalizing tube for supplying the control electrode of the latter with biasing potential only during operative periods of said repeater. I

6. In combination a space di-schargeoscillator, a space discharge repeater coupled thereto, a source of anode potential connected to both oscillator and repeater, an oscillation circuit in the anode circuit of said repeater, an impedance in the anode circuit of said oscillator, means in the anode circuit of said repeater to control the current flow therein, a load equalizing space discharge tube conof the repeater is closed.

' BUD OLF URTEL. 

